Abstract: According to the high-gas constructed coal seam of 2012 working face in a coal mine of Hebei, in order to reduce losses, the working face support, shearer and other equipments were withdrew, then it unsealed the working face. After investigating the process of spontaneous combustion, the determination of spontaneous combustion hazard area and gas analysis before unsealing was done, and the unsealing technical measures such as repairing the air-input and output roadways, nitrogen injection in goaf, gel injection after support, gases and temperature monitoring of the whole process was developed.